This proposal will develop and test the feasibility of a 2-year, family-based, weight management program. Subjects will be 50 overweight preschool child/overweight parent pairs randomized into either a treatment group with the parent as the mediator of change or a control group. Two behavioral models will be combined to help parents enhance their parenting skills (social learning theory) and develop strategies to better manage their own weight (cognitive behavioral therapy). The intervention for the child will provide age-specific, healthy eating patterns with increases in daily physical activity to enable weight stabilization or small weight gains of no more than 4.5 lb. (2 kg) per year, to allow for a gradual decline in BMI as children grow and minimize body fatness to prolong the period before normal adiposity rebound occurs. The intervention for the adult will follow our traditional model which focuses on weight loss goals of -500 kcal/day or -1 lb./wk and prevention of weight regain. The parent/child pairs will attend all sessions together and the child's intervention will be combined with those of the parent. After a brief socialization activity with snacks, the child will be taken to a play/educational group while parents attend group treatment sessions. The intervention for the first year will consist of 33 group sessions with 3 individual drop-in sessions during the last 3 months; the second year will consist of 4 quarterly group sessions and 12 monthly drop-in sessions. The control group will receive health education only, consisting of the adult and child versions of the dietary and activity guidelines, food guide and activity pyramids and health report cards. Both groups will receive assessments at baseline, 12 and 24 months. The primary dependent variable for the parent is weight change and for the child is BMI. Secondary dependent variables include selected biopsychosocial measures (e.g. body mass index, circumferences, skinfolds, percent body fat by DXA and bioimpedance, blood lipid profiles, glucose and insulin, blood pressure, pulse and heart rate on both the parent and child; quality of life, general well being, eating and activity self efficacy and social support in the adult; and parental reports of their child's activity, food intake and related behaviors). Four hypotheses will be tested: Hl: The child in the treatment group will maintain weight or gain no more than 2 kg year or 4 kg (9.5 lb.) in 2 years( or have an age-sex appropriate average change in BMI); whereas, their parent will be able to lose approximately 10 percent (approximately 20 lb.) of their weight at one year and maintain this weight loss at 2 years; H2: The child and parent in the intervention group will develop significantly healthier eating and physical activity patterns than those in the control group as measured by food and activity records, food frequencies, recalls, activity monitor readings and self-monitoring charts; H3: parents in the treatment group will report significantly improved parenting skills around feeding/food and physical activity compared to the control group; and, H4: Both the child and parent in the treatment group will exhibit significantly better biopsychosocial profiles than the control group at 12 and 24 months. Innovative interventions are needed for prevention of excessive weight gain in preschool children. With the successful implementation of this pilot study, a multicenter clinical trial will be developed using the materials/methods by study investigators.